It is well-known that ethylenically unsaturated compounds can be produced from hydrochlorocarbons by means of a cracking or pyrolysis process by splitting off a molecule of hydrogen chloride. The cracking is accomplished in the absence of a catalyst by heating the hydrochlorocarbon in an inert atmosphere under high temperature and pressure. Usually a temperature in the range of about 500.degree. C. to about 600.degree. C. and a pressure of about 100 to 600 psig is used. The generation of such energy, of course, is expensive.
In European Pat. No. 2,021, a catalyst system comprising a zeolite which has been treated or reacted with a volatile Lewis acid was disclosed for the dehydrohalogenation of ethylene dichloride. Suitable catalysts include faujasite Y zeolite reacted with TiCl.sub.4.
Synthetic activated divalent cation exchanged sodium zeolite A was disclosed in U.S. Pat. No. 2,920,122 as suitable in the dehydrochlorination of halo-substituted hydrocarbons. Specific examples included the conversion of tertiary butyl chloride to isobutene.
In U.S. Pat. No. 3,927,131, at column 4, lines 28-50, Table I, the use of a synthetic zeolite, SK-120, containing 10 percent rare earths of unspecified identity and 0.5 percent palladium in the dehydrohalogenation of aliphatic hydrochlorocarbons was disclosed. Temperatures employed were from about 400.degree. C.-600.degree. C.
Prior art processes for dehydrochlorination of hydrochlorocarbons have required that the synthetic zeolite be modified by reaction with Lewis acids or by exchange of divalent cations or incorporation therein of rare earths or noble metals. It would be desirable to provide a synthetic zeolite catalyst for the dehydrochlorination of hydrocarbons that does not require preparation or modification in the above ways.
Prior art processes have also obtained only limited conversions of hydrochlorocarbons thereby requiring long contact or reaction times or multiple passes of the hydrochlorocarbon over the catalyst bed.
It would be desirable to provide a catalyst system that allows the artisan to prepare dehydrochlorination products in relatively high conversions using reduced reaction or contact times without the formation of substantial quantities of by-products.
It would further be desirable to provide a catalyst system that will obtain the dehydrochlorination of hydrochlorocarbons at relatively mild reaction temperatures, thereby resulting in reduced energy consumption.
These objects and others that will become readily apparent to the skilled artisan have now been obtained according to the instant invented process.